/* Soot - a J*va Optimization Framework
 * Copyright (C) 1997-1999 Raja Vallee-Rai
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

package soot.jbco.bafTransformations;

import java.util.*;

import soot.*;
import soot.baf.*;
import soot.baf.internal.AbstractOpTypeInst;
import soot.jbco.IJbcoTransform;
import soot.jimple.DoubleConstant;
import soot.jimple.FloatConstant;
import soot.jimple.IntConstant;
import soot.jimple.LongConstant;
import soot.jimple.NullConstant;
import soot.toolkits.scalar.GuaranteedDefs;

/**
 * @author Michael Batchelder 
 * 
 * Created on 16-Jun-2006 
 */
public class FixUndefinedLocals extends BodyTransformer implements IJbcoTransform {

  private int undefined = 0;
  
  public static String dependancies[] = new String[] {"bb.jbco_j2bl", "bb.jbco_ful", "bb.lp" };

  public String[] getDependancies() {
    return dependancies;
  }
  
  public static String name = "bb.jbco_ful";
  
  public String getName() {
    return name;
  }
  
  public void outputSummary() {
    out.println("Undefined Locals fixed with pre-initializers: "+undefined);
  }

  protected void internalTransform(Body b, String phaseName, Map<String,String> options) {
    //  deal with locals not defined at all used points
    
    int icount = 0;
    boolean passedIDs = false;
    Map<Local,Local> bafToJLocals = soot.jbco.Main.methods2Baf2JLocals.get(b.getMethod());
    ArrayList<Value> initialized = new ArrayList<Value>();
    PatchingChain<Unit> units = b.getUnits();
    GuaranteedDefs gd = new GuaranteedDefs(new soot.toolkits.graph.ExceptionalUnitGraph(b));
    Iterator<Unit> unitIt = units.snapshotIterator();
    Unit after = null;
    while (unitIt.hasNext()) {
      Unit u = unitIt.next();
      if (!passedIDs && u instanceof IdentityInst) {
        Value v = ((IdentityInst)u).getLeftOp();
        if (v instanceof Local) {
          initialized.add(v);
          icount++;
        }
        after = u;
        continue;
      }
      
      passedIDs = true;
      
      if (after == null) {
        after = Baf.v().newNopInst();
        units.addFirst(after);
      }
      
      List<?> defs = gd.getGuaranteedDefs(u);
      Iterator<ValueBox> useIt = u.getUseBoxes().iterator();
      while (useIt.hasNext()) {
        Value v = ((ValueBox) useIt.next()).getValue();
        if (!(v instanceof Local) || defs.contains(v) || initialized.contains(v))
          continue;

        Type t = null;
        Local l = (Local) v;
        Local jl = (Local) bafToJLocals.get(l);
        if (jl != null) {
          t = jl.getType();
        } else {
          // We should hopefully never get here. There should be a jimple 
          // local unless it's one of our ControlDups
          t = l.getType();
          if (u instanceof OpTypeArgInst) {
            OpTypeArgInst ota = (OpTypeArgInst) u;
            t = ota.getOpType();
          } else if (u instanceof AbstractOpTypeInst) {
            AbstractOpTypeInst ota = (AbstractOpTypeInst) u;
            t = ota.getOpType();
          } else if (u instanceof IncInst)
            t = IntType.v();
          
          if (t instanceof DoubleWordType || t instanceof WordType) {
            throw new RuntimeException("Shouldn't get here (t is a double or word type: in FixUndefinedLocals)");
          }
        }
        Unit store = Baf.v().newStoreInst(t, l);
        units.insertAfter(store,after);
        
        // TODO: is this necessary if I fix the other casting issues?
        if (t instanceof ArrayType) {
          Unit tmp = Baf.v().newInstanceCastInst(t);
          units.insertBefore(tmp,store);
          store = tmp;
        }
        /////
        
        Unit pinit = getPushInitializer(l, t);
        units.insertBefore(pinit,store);
        /*if (t instanceof RefType) {
          SootClass sc = ((RefType)t).getSootClass();
          if (sc != null)
            units.insertAfter(Baf.v().newInstanceCastInst(t), pinit);
        }*/
        
        initialized.add(l);
      }
    }
    
    if (after instanceof NopInst)
      units.remove(after);
    undefined += initialized.size() - icount;
  }

  public static PushInst getPushInitializer(Local l, Type t) {
    if (t instanceof IntegerType) {
      return Baf.v().newPushInst(IntConstant.v(soot.jbco.util.Rand.getInt()));
    } else if (t instanceof RefLikeType || t instanceof StmtAddressType) {
      return Baf.v().newPushInst(NullConstant.v());
    } else if (t instanceof LongType) {
      return Baf.v().newPushInst(LongConstant.v(soot.jbco.util.Rand.getLong()));
    } else if (t instanceof FloatType) {
      return Baf.v().newPushInst(
          FloatConstant.v(soot.jbco.util.Rand.getFloat()));
    } else if (t instanceof DoubleType) {
      return Baf.v().newPushInst(
          DoubleConstant.v(soot.jbco.util.Rand.getDouble()));
    }
    
    return null;
  }
  
  /*
   * 
  private Unit findInitializerSpotFor(Value v, Unit u, UnitGraph ug,
      GuaranteedDefs gd) {
    List preds = ug.getPredsOf(u);
    while (preds.size() == 1) {
      Unit p = (Unit) preds.get(0);
      //if (p instanceof IdentityInst)
      //  break;

      u = p;
      preds = ug.getPredsOf(u);
    }

    if (preds.size() <= 1)
      return u;

    ArrayList nodef = new ArrayList();
    Iterator pIt = preds.iterator();
    while (pIt.hasNext()) {
      Unit u1 = (Unit) pIt.next();
      if (!gd.getGuaranteedDefs(u1).contains(v)) {
        nodef.add(u1);
      }
    }

    if (nodef.size() == preds.size())
      return u;

    if (nodef.size() == 1)
      return findInitializerSpotFor(v, (Unit) nodef.get(0), ug, gd);

    throw new RuntimeException("Shouldn't Ever Get Here!");
  }*/
}
